Novel organosiloxane-silicate copolymers



3,341,469 NOVEL ORGANOSILOXANE-SILICATE COPOLYMERS Arthur N. Pines,Snyder, and Eugene A. Zientek, Tonawanda, N.Y., assignors to UnionCarbide Corporation, a corporation of New York No Drawing. Originalapplication Apr. 26, 1961, Ser. No. 105,535. Divided and thisapplication Dec. 15, 1964, Ser. No. 418,532

7 Claims. ((31. 252-689) This application is a division of applicationSer. No. 105,535, filed Apr. 26, 1961.

This invention relates to organosilicon compounds and, moreparticularly, to copolymers of organosiloxanes and silicates. Thisinvention further relates to a process for inhibiting corrosion and toinhibited aqueous alcohol compositions wherein the novel copolymers areemployed as corrosion inhibitors.

The copolymers of this invention contain (1) from 0.1 to 99.9 parts byweight (per 100 parts by weight of the copolymer) of (a) at least onesiloxane group represented by the formula:

wherein R is a methyl, ethyl, phenyl or vinyl group and/ or (b) at leastone siloxane group represented by the formula:

i a 2a]bslO4 (b+c) 2 (2) wherein Y is a cyano group, CH OH) CH(OH)-group,

CH OH) CH OH) CH group,

or R"(OCH CH (OC H O- group, R" is a monovalent hydrocarbon group or ahydrogen atom, n has a value of at least one and preferably has a valuefrom 1 to 20, in has a value from to 20 or higher and preferably has avalue from 0 to 10, the ratio of n to m is at least 2 to 1, a has avalue of at least 2 and up to 10 or higher (preferably from 2 to 4inclusive), C,,H is an alkylene group, the group represented by Y isseparated from the silicon atom by at least two successive carbon atomsof the group represented by C H b has a value from 1 to 3 inclusive(preferably 1), R is a monovalent hydrocarbon group, c has a value fromO to 2 inclusive and (Ii-+0) has a value from 1 to 3 inclusive; and (2)from 0.1 to 99.9 parts by weight (per 100 parts by weight of thecopolymer) of at least one silicate group represented by the formula:

group,

[Mi d'OhSiOl-e i wherein M is a cation that forms a water solublesilicate, d is the valence of the cation represented by M and has avalue of at least one and e has a value from 1 to 3 inclusive.

Preferably, the copolymers of this invention contain from to 45 parts byweight (per 100 parts by weight of the copolymer) of groups representedby Formula 1 3,341,469 Patented Sept. 12, 1967 and/or 2 and from 55 to85 parts by weight (per 100 parts by weight of the copolymer) of groupsrepresented by Formula 3.

In addition to the groups represented by Formulae 1 and/or 2 and 3, thecopolymers of this invention can contain groups represented by theformulae:

Rlllsiolis R' SiO (4b) wherein R is a monovalent hydrocarbon group otherthan a methyl, ethyl, phenyl or vinyl group and R has the above-definedmeaning. These latter copolymers contain from 0.1 to 99.8 parts byweight of groups represented by Formula 1 and/or 2, from 0.1 to 99.8parts by weight of groups represented by Formula 3 and from 0.1 to 99.8parts by weight of groups represented by Formulae 4a, 41) and/or per 100parts by weight of the copolymer. Preferably these latter copolymerscontain from 10 to 45 parts by weight of groups represented by Formula 1and/ or 2 from to parts by weight of groups represented by Formula 3 andfrom 5 to 15 parts by weight of groups represented by Formulae 4a, 4band/or 40 per parts by weight of the copolymer.

The groups represented by Formula 1 are the methylsiloxy, ethylsiloxy,phenylsiloxy and vinylsiloxy groups.

Illustrative of the groups represented by Formula 2 are thebeta-cyanoethylsiloxy, gamma-cyanopropylsiloxy, delta-cyanobutyl,gamma-cyanoisobutylsiloxy, beta-cyano ethyl (methyl) siloxy,

. Illustrative of the groups represented by Formula 3 are the groupshaving the formulae: KOSiO NaOSiO (KO) SiO, (CH NOSiO (NaO) SiO, (KO)SiO and (NaO) SiO The silicon atom in each group represented by Formulae1, 2 and 3 is bonded through at least one oxygen atom to another siliconatom. In addition to the substituents indicated in these formulae, someor all of the silicon atoms in the groups represented by Formulae 1, 2and 3 can be bonded to hydrogen atoms through oxygen (in which case theinhibitor contains the Si-OH group). Furthermore, some or all of thesilicon atoms in the groups represented by the Formulae 1 and 3 can alsobe bonded to monovalent hydrocarbon groups through oxygen (in which casethe inhibitors contain SiOR groups) or to the cations represented by Mthrough oxygen (in which case the inhibitor contains additional M OSigroups).

Illustrative of the monovalent hydrocarbon groups represented by R inFormulas 2, 4b and 4c and R" in Formula 2 are the linear alkyl groups(for example the methyl, ethyl, propyl, butyl and octadecyl groups), thecyclic alkyl groups (for example the cyclohexyl and cyclopentyl groups),the linear alkenyl groups (for example the vinyl'and the butenylgroups), the cyclic alkenyl groups (for example the cyclopentenyl andthe cyclohexenyl groups), the aryl groups (for example the phenyl andnaphthyl groups), the alkaryl groups (for example the tolyl group) andthe aralkyl groups (for example the benzyl and beta-phenylethyl groups).Preferably these monovalent hydrocarbon groups contain up to six carbonatoms.

Illustrative of the cations that form water soluble silicatesrepresented by M in Formula 3 are the various monovalent and polyvalentinorganic and organic cations that form water soluble silicates. Typicalmonovalent cations are alkaline metal cations [e.g. the sodium, potassium, lithium and rubidium cations]; and the tetraorgano ammoniumcations [c.g. the tetra(alkyl) ammonium cations such as thetetra(methyl) ammonium cation, and the tetra(ethyl) ammonium cation; thetetra (mixed aryl-alkyl and mixed aralkyl-alkyl) ammonium cations suchas the phenyltrimethyl ammonium cation and the benzyltrimethyl ammoniumcation; and the tetra(hydroxyalkyl) ammonium cation such as thetetra(hydroxyethyl) ammonium cation]i Typical of polyvalent cations arethose produced by converting polyamines such as guanidine or ethylenediamine to poly ammonium hydroxides. Illustrative of such polyvalentcations are and H N(CH NH In the case of monovalent cations, the valueof d in Formula 3 is one and, in the case of the polyvalent cations, thevalue of d in Formula 3 is at least 2 and preferably 2 or 3. The mostpreferred cations are sodium and, more especially, potassium.

Groups represented by Formula 4a include the amylsiloxy,beta-phenylethylsiloxy and the hexylsiloxy groups. Groups represented byFormula 4b include the dimethylsiloxy, diethylsiloxy,phenyl(methyl)siloxy and ethyl- (vinyl)siloxy groups. Groups representedby Formula 40 include the trimethylsiloxy and triphenylsiloxy groups.

The copolymers of this invention can be produced by reacting (A) anorganosiloxane composed only of groups represented by Formula 1 and/ or2 or an organosiloxane composed of groups represented by Formula 1 and/or 2 and groups represented by Formulae 4a, 4b and/or 4c, and (B) awater soluble silicate composed of groups represented by Formula 3.

The starting organosiloxanes employed in producing the copolymers ofthis invention include such starting homopolymers as those composed onlyof CH SiO C H5SlO1 5 r groups and such starting copolymers as thosecomposed of one or more of the latter groups and one or more Ol'CGHCH2CH2SIOL5 groups.

Starting organosiloxanes combining only groups represented by Formulae 1and/ or 2 are conveniently produced by hydrolyzing and condensingorganosilanes represented by the formulae:

RSiX (5) and/ or I i [YOnHln]hSlX4-(b+c) (6) wherein a, b, c, (a-I-b)and R' have the above-defined meanings, Y has the meaning defined for Yor is a 4; group and X is an alkoxy group (e.g. a methoxy, ethoxy,propoxy or butoxy group). The epoxy-containing groups represented by Yare converted to dihydroxy groups during the hydrolysis and condensationof the silane according to the equation:

0 HO OH C C E20 o-o Starting organosiloxanes containing groupsrepresented by Formulae 4a, 4b and/ or 40 as well as groups representedby Formulae l and/ or 2 are conveniently produced by cohydrolyzing andcondensing organosilanes represented by Formulae 5 and/or 6 andorganosilanes represented by the formula:

and/ or R' SiX wherein R, R and X have the above-defined meaning.

Organosilanes represented by Formula 6 wherein Y is an epoxy-containinggroup can be produced by the platinum-catalyzed reaction of anepoxy-containing olefin (e.g. allyl glycidyl ether) and ahydr-ogensilane represented by the formula:

l H SiXi- M c) (8) wherein R, X, b and 0 have the above-definedmeanings. Organosilanes represented by Formula 6 wherein Y is a cyanogroup can be produced by the triphenylphosphine or trialkylaminecatalyzed reaction of an olefinic nitrile (e.g. acrylonitrile) and ahydrogensilane represented by Formula 8.

The starting silicates used in producing the copolymers of thisinvention are water soluble and composed of cation oxide units (i.e. M Owhere M is the cation of a water soluble silicate and a is the valenceof the cation) and silicon dioxide units (i.e. SiO These silicates canbe represented by the average formula:

( z/d )n( 2) wherein n has a value from 0.5 to 4, or preferably from 1.0to 2.5, and wherein M and d have the above-defined meanings. Alternatelysuch silicates can be described as composed of groups represented byFormula 3. Illustrative of these silicates are the alkali metalorthosilicates [which have the formula (M O) (SiO where M is an alkalimetal], the alkali metal metasilicates [which have the formula (M 0)(SiO the alkali metal tetrasilicates [which have the formula (M O)(SiOthe alkali metal disilicates [which have the formula (M 0) (SiO and thetetra(organo)ammonium silicates. Specific examples of these silicatesare potassium metasilicate, sodium orthosilicate, potassium disilicate,lithium orthosilicate, lithium metasilicate, lithium disilicate,rubidium disilicate, rubidium tetrasilicate, mixed silicates (e.g. (NaO-Li O'2SiO and K O-Li O-4SiO tetra(methyl) ammonium silicate,tetra(ethyl) ammonium silicate, phenyltrimethyl ammonium silicate,benzyltrimethyl ammonium silicate, guanidine silicate andtetra(hydroxy-ethyl) ammonium silicate. The preferred silicates aresodium and potassium silicates, especially sodium disilicate andpotassium disilicate.

The starting silicate used in producing the copolymers of this inventioncan be added to the reaction mixture as such or it can be formed in situby adding the appropriate hydroxide (e.g. NaOH or KOH) and silica to thereaction mixture.

Mixtures of the above-described organosilanes and. Water solublesilicates can be formed. These mixtures can contain water initially orcan be anhydrous initially and then mixed with water. The water convertsthe organosilanes to organosiloxanes in situ by hydrolysisandcondensation. The organosiloxanes so formed can react with thesilicate to produce a copolymer of this invention.

The organosilanes represented by Formulae 5, 6, 7a, 7b and 7c arepartially converted to organosiloxanes by hydrolysis and condensationreactions when mixed with water even at room temperature. Heating themixture of the silane and water serves to complete the reaction which iscatalyzed by the silicate. The organosiloxanes so formed then react withthe silicate. Distillation of the alcohol formed in the hydrolysis canbe performed to remove the alcohol to concentrate the copolymer.

The amount of water used in the latter process for producing thecopolymers of this invention is at least that amount required tohydrolyze at least one group in each silane represented by X in Formulae5, 6, 7a, 7b, and 7c. Amounts of water in excess of that amount requiredto hydrolyze all of the groups represented by X are usually preferredsince it is generally desirable to have an excess of water present toserve as a medium within which the inhibitors can be formed. Thus, from0.5 to 2000 moles of water per mole of the silane represented byFormulae 5, 6, 7a, 7b and 7c are preferred. Although other amounts ofwater can be used they are usually not desirable since lesser amountsresult in incomplete reaction and since greater amounts result inexcessive dilution of the reaction mixture.

The temperature at which the starting organosiloxane and silicate aremaintained and at which they react to produce the copolymers of thisinvention can vary widely. Thus, temperatures from 20 C. to 150 C. canbe used. However, temperatures from 20 C. to 115 C. are preferred. Theuse of other temperatures is generally undesirable since no advantage isgained thereby. When the starting siloxane is being formed in situ, theconversion of the silanes represented by Formulae 5, 6, 7a, 7b and 70 tosiloxanes is essentially completed by heating the mixture. The alkoxygroups in the starting silanes are converted to alcohols that can bevolatilized during the heating.

The copolymers of this invention are remarkably soluble in aqueousliquids (i.e. in water and in solutions containing water and watersoluble materials such as water soluble organic liquids). Moreover,these copolymers inhibit to a remarkable degree of the corrosion ofmetals that are in contact with aqueous liquids to which the copolymershave been added. In particular, aqueous alcohol solutions containingcopolymers of this invention cause remarkably less corrosion thanuninhibited aqueous alcohol solutions and hence are admirably suited asnoncorrosive coolants for use, for example, in the cooling systems ofinternal combustion engines.

When the copolymers of this invention are used as corrosion inhibitors,the copolymer is added to an aqueous liquid and, for best results, thecopolymer is then uniformly dispersed throughout the liquid. Anysuitable means can be used to disperse th copolymer throughout theliquid. Thus, in the case of moving liquids that are in contact with themetal to be protected, the copolymer can be added to the liquid whilethe liquid is in use and dispersion of the copolymer throughout theliquid is achieved by the movement of the liquid. However, the copolymercan be added to the liquid (prior to the use of the liquid in contactwith the metal to be protected) and the copolymer can be dispersedthroughout the liquid by stirring the liquid. This latter procedure ispreferred where the liquid is to be stored or Where the liquid undergoeslittle movement when in use. These procedures allow the copolymer toreadily dissolve in the water or aqueous solution.

When the copolymers of this invention are used as corrosion inhibitors,the copolymer can be added as such to the aqueous liquid. Alternately,materials can be added to the aqueous liquid which react with the waterin the liquid to produce the copolymer in situ. By way of illustration,a silane represented by Formula 5 or 6 or a mixture of silanesrepresented by Formulae 5, 6, 7a, 7b and/ or 70 can be added to anaqueous liquid along with a water soluble silicate to produce thecopolymer in the liquid.

The copolymers of this invention are generally useful to the protectionof metals that come into contact with any aqueous liquid. Suitableliquids are pure water, aqueous solutions containing inorganic solutesand solutions containing water and water soluble organic compounds,especially water soluble or miscible organic liquids. Illustrative ofsuitable aqueous solutions containing inorganic solutes are aqueoussodium or potassium chloride refrigerating solutions, corrosive wellwater or river water containing normal chlorides, carbonates andsulfates which may be used as process or cooling water in industry, andthe like. Illustrative of suitable solutions containing water and awater soluble organic liquid are solutions containing water andmonohydric or polyhydric alcohols (e.g. methanol, ethanol, propanol,ethylene glycol, propylene glycol and glycerol), hydroxyl and alkoxyend-blocked polyalkylene oxides (such as hydroxyl end-blockedpolyethylene oxide), sulfoxides (such as methylsulfoxide), formamides(such as dimethylformamide) or cyclic ethers free of olefinicunsaturation (such as tetrahydrofuran, dioxane and the like). Suitablesolutions containing water and a water soluble organic liquid shouldcontain at least 0.1 part by weight, or preferably at least 5.0 parts byweight, of water per parts by weight of the water and the organicliquid.

The copolymers of this invention are generally useful in the protectionof all metals and alloys that are used in industrial processes andapparatus. Metals whose corrosion is retarded by the copolymers of thisinvention include the metals below sodium in the electro'rnotive series{c.g. magnesium, aluminum, copper, iron, manganese, nickel, lead,silver, tin, beryllium and zinc) as well as the alloys of such metals(e.g. brass, bronze, solder alloys, steel and the like). Such metals aresolids at 25 C. and normally become corroded when in prolonged contactwith water, particularly when the water is at elevated temperatures and/or contains electrolytes (e.g. acidic solutes). The copolymers of thisinvention are particularly useful in the protection of brass, iron,copper and aluminum.

The amount of the copolymers of this invention used in inhibitingcorrosion of metals in contact with aqueous liquids is dependent uponthe temperature, type of metal or metals being protected, type of anyorganic liquid in the solution, pH of the aqueous liquid, velocity ofthe aqueous liquid, inorganic solutes (e.g. electrolytes such aschlorides, sulfates and bicarbonates) in the aqueous liquid and priortreatment or corrosion of the metal. Generally, from 0.01 part per 10parts by weight of the copolymer per 100 parts by weight of the aqueousliquid to which the inhibitor is added are useful. Preferably from 0.5part to 2.5 parts by weight of the copolymer per 100 parts by weight ofthe aqueous liquid are used.

Compared with known inhibitors used in preventing corrosion of metalsthat are in contact with water, the copolymers of this invention providenumerous advantages. Thus, the copolymers can be added to a wide varietyof aqueous solutions and inhibit the corrosion of a wide variety ofmetals. In addition, the copolymers are effective over a widetemperature range and these inhibitors do not cause the liquids in whichthey are employed to foam excessively. Furthermore, these copolymers donot promote the decomposition of any organic liquids present in theliquid nor do they attack other organic materials with which the liquidmay come in contact.

The copolymers of this invention are useful in preventing the corrosionof metals that are cleaned by corrosive solutions or that are used incooling coils, boilers, refrigeration and air conditioning equipment,heat exchange tubes, storage tanks for liquids, pipes, solventcontainers, tank cars, ballast tanks containing sea water and the like.

The copolymers of this invention are particularly useful to inhibitingthe corrosion of the cooling systems of internal combustion engines incontact with aqueous alcohol coolant compositions.

Inhibited alcohol compositions containing an alcohol and a copolymer ofthis invention as a corrosion inhibitor are remarkably useful asanti-freezes and coolants for the cooling systems of internal combustionengines. These anti-freezes are inhibited alcohol solutions Containingno water or relatively small amount of water and these coolants areinhibited alcohol solutions containing relatively large amounts ofwater. The concentrates or anti-freeze compositions are adapted toeconomical shipment and storage and the coolants are adapted to use, assuch, as heat transfer media in the coling systems of internalcombustion engines. In practice, the concentrate can be shipped to thepoint where it is to be added to the cooling system and there it can bediluted to form a coolant. Water imparts desirable properties to boththe concentrate and coolant compositions (e.g. small amounts of waterserve to lower the freezing point of the concentrate compositions andlarge amount of water impart good heat transfer properties to thecoolant compositions). These compositions can contain from part byweight to 900 parts by weight of water per 100 parts by weight of thealcohol. It is desirable that the coolant compositions contain from 30to 900 parts by weight of water per 100 parts by weight of the alcohol.It is desirable that the concentrates contain from 0.1 part to 10 partsby weight (or more desirably from 2 parts to 5 parts by weight) of waterper 100 parts by weight of the alcohol. In the latter case, the amountof water with which the concentrate compositions is mixed to provide acoolant should be such that the resulting coolant composition containsfrom 30 parts to 900 parts by weight of Water per 100 parts by weight ofthe alcohol. The relative amount of Water and alcohol in thesecompositions can be varied to lower the freezing point of thecompositions by the desired amount. The pH of the inhibited aqueousalcohol compositions of this invention should be greater than seven tominimize corrosion of metals with which the compositions come intocontact.

If desired, various additives can be added to the abovedescribedinhibited alcohol compositions in particular instances for impartingspecial properties. By way of illustration, anti-foam agents,identifying dyes, pH indicators, conventional inhibitors, sealants whichprevent leakage of the coolant from the cooling system, anti-creepagents which prevent seepage of the coolant into the crankcase and thelike can be added to these compositions.

The above-described inhibited alcohol compositions can be formed in anyconvenient manner, e. g. by adding an alcohol, the organosiliconinhibitor and water to a container and stirring the mixture.

In addition to being useful as corrosion inhibitors, the copolymers ofthis invention are useful as coating and laminating resins. Thus aqueoussolutions of these copolymers can be applied to steel surfaces byconventional coating methods and heat applied to volatilize the waterand to form a protective coating on the steel surface. In addition thesecopolymers can be used to bind successive layers of glass fibers inaccordance with conventional procedures to produce laminates.

The improvements in corrosion inhibition resulting from the use of thecopolymers of this invention were found and evaluated by elaboratelaboratory tests designed to simulate field conditions.

Two-Hundred Hour Corrosion Test.--This is a laboratory test which hasproven over many years to be useful in evaluating inhibitors for use inaqueous alcohol antifreeze solutions such as are used in the coolingsystems of internal combustion engines. The test involves immersingclean strips of metal (usually iron, aluminum, brass and copper) and abrass coupon on which is a spot of solder, composed of 50 wt.-percentlead and 50 wt.-percent tin, in the test fluid with heating and aerationfor a period of 200 hours. After this exposure, the specimens arecleaned and corrosion of the metal strips is measured by weight loss inmilligrams. The corrosion of the spot of solder on the brass coupon isgiven a rating (called Solder Spot Rating, abbreviated SS in theexamples) by visual inspection with a rating of 6 indicating little orno corrosion and a rating of 0 indicating very severe corrosion.

Each test unit consists of 600 milliliter glass beaker equipped with areflux condenser and an aeration tube. The test specimens are cut frominch sheet stock usually with a total surface area of about nine (9)square inches. Test temperature is C. and aeration rate is 0.028 cubicfeet per minute. Specimens are separated with Z shaped glass rods andare covered with 350 cc. of solution. The water used in preparing testsolutions has 100 parts per million added of each of bicarbonate,chloride, and sulfate ions as sodium salts. This gives an acceleratedcorrosion rate that simulates the corrosion rate that prevails whennatural water is used to dilute anti-freeze compositions in actualpractice. Duplicate tests are run simultaneously and both values or theaverage values of Weight loss, final pH and final RA (defined below) aregiven.

The Reserve Alkalinity of an anti-freeze composition is a measure of theability of the composition to resist a decrease in pH due to thepresence of acidic materials such as are produced by the decompositionof ethylene glycol. Reserve Alkalinity (abbreviated RA in the examples)is determined by titrating a sample (about 10 cc.) of the compositionwith 0.1 N aqueous hydrochloric solution. From the number of millilitersof the acid actually required to neutralize the sample, the number ofmilliliters of acid that would be required to neutralize 100 millilitersof the composition of it contained a water to ethylene glycol ratio of2:1 on a volume basis is computed and this latter number is the ReserveAlkalinity of the composition.

In the following examples, BR is used as an abbreviation for brass. Allof the inhibited alcohol compositions of this invention described in theexamples below were single phase compositions.

Example I A copolymer of this invention (Copolymer A) was produced byforming a mixture of one gram of and 100 grams of a solution containing1.55 wt.-percent potassium disilicate, 3.6 wt.-percent water and 94.85wt.-percent ethylene glycol. The mixture was shaken and then allowed tostand for 16 hours at room temperature. There was so produced a solutionof a copolymer composed of CH SiO groups and KOSiO groups dissolved inaqueous ethylene glycol.

Example ll Following the above-described procedures copolymers of tl11sinvention were produced from K Si O and the following silanes:

Oopolymer Formula of Starting Silaue NCCHzOHaSKO CzHs); CHaSl(ONa) O CH(O CHzCH2)2O OHzCHgOHzSKO 0115):,

In each preparation 10 parts of the starting silane per 15.5 parts of KSi O were reacted (by weight).

The groups present in these various inhibitors and the relative amountsof these groups are shown below:

Siloxane Groups KOSiO. 5 Copolymer Groups,

Parts 1 Formula Parts 19.3 80.7 21.3 78.7 21.3 78.7 25.8 74.2 30.0 70.0H20 23. 6 76.4 CHsSi(ONa) 39.2 60.8 CH3) CHzCH7 zO CH7CHgCHzslO1.5 .u32. 3 67. 7

1 By weight per 100 parts by weight of the copolymer.

Example III 20 Aqueous ethylene glycol solutions of several copoly- S Fmers of this invention were stored in closed containers at 100 C. todetermine the storage stability of such solutions. The solutionscontained the indicated amount of the copolymers, 94.9 parts by Weightof ethylene glycol and 3.6 parts by weight of water. For comparisonpurposes, similar storage tests were run on aqueous ethylene glycolsolutions of a silicate and other silicone-silicate copolymers. Theresults obtained are shown below.

Copolymers of This Invention Amount Hours Till Gel Formed Copolymer A 1.92 32 to 48 Copolymer B. 1. 97 32 to 48 Copolymer O. 1.97 7 to 24Copolymer D. 2.09 32 to 48 Gopolymer E. 2. 15 1, 000

Copolymer F 2. 03 1, 000

Copolymer G, 2. 55 1, 000

Other Materials Amount Hours Till Gel Formed Silicate composed of K0$101.5 1. 55 7 Copolyrner composed of 24.7 wt. percent C5Hn SiOl-5 and75.3 wt. percent KOSiO1. 2.06 7 Copolymer of 24.4 wt. percent (CHmSiOand 75.6 wt. percent KOSiO 2.05 7 Copolymer of 27.2 wt. percentC:HuSi(C2H)3O and 72.8 Wt. percent KOSiOH. 2.13 7 Copolymer of 28.2 wt.percent OzNCuHaSlO E and 71.8 wt. percent KOSiO1. 2.16 7

Example IV The ZOO-Hour Corrosion Test was conducted employingcopolymers of this invention as corrosion inhibitors. For comparisonpurposes, the test was also run employing no inhibitor and also asilicate as a corrosion inhibitor. The test liquid contained 100 partsby weight of ethylene glycol and 180 parts by weight of water to whichwere added one part by weight of the indicated inhibitor.

pH RA Weight Losses (mg.

per 9 sq. in.) Inhibitor 8.8.

I F I F Fe Al BR Cu copolymer A 11.1 10.9 56 45 7 0 23 25 6. 5 CopolymerB 11.0 11.0 60 45 21 10 17 40 6 Copolymer E 11.2 10.8 57 62 3 0 1 4 5Copolymer F 10. 9 10.6 56 40 5 0 1 5 5. 5 Gopolymer G 11. 3 l0. 8 70 564 0 3 14 5. 5 KzSizOrs 11. 2 l1. 2 60 48 11 4 10 17 6 None 7. 1 6. 2 0 0663 10 115 52 4. 5

l I denotes initial value.

2 F denotes final value.

3 Solder Spot Rating.

4 1.55 parts by weight inhibitor used in this run.

As used herein the symbol denotes the cyclohexyl group (C H Thecopolymers of this invention can contain SiO groups in addition to thegroups indicated above. Copolymers containing SiO groups can be producedby employing starting organosiloxanes containing SiO groups.

What is claimed is:

1. A process for inhibiting the corrosion of metals below sodium in theelectromotive series that come in contact with aqueous liquids, saidprocess comprising adding to the liquid a corrosion inhibiting amount ofa copolymer consisting essentially of:

(1) from 0.1 to 99.9 parts by Weight of (a) a member selected from thegroup consisting of siloxane groups represented by the formula:

wherein R is a member selected from the group consisting of the methyl,ethyl, phenyl and vinyl groups and (b) siloxane groups represented bythe formula:

[YCuH25]bSiO4 (b+c) wherein Y is a member selected from the groupconsisting of the cyano group, CH (OH)CH(OH) group, CS (OH)CH(OH)CHgroup,

group, R" is a member selected from the group consisting of themonovalent hydrocarbon groups and the hydrogen atom, n has a value of atleast 1, m has a value from 0 to 20 inclusive, the ratio of n to m is atleast 2 to l, a has a value of at least 2, C H is an alkylene group, thegroup represented by Y is separated from the silicon atom by at leasttwo successive carbon atoms by the group represented by C H b has avalue of from 1 to 3 inclusive, R is -a monovalent hydrocarbon group, 0has a value from 0 to 2 inclusive, (b+c) has a value from 1 to 3inclusive; and

(2) from 0.1 to 99.9 parts by weight of at least one silicate grouprepresented by the formula:

wherein M is a cation that forms a water soluble silicate selected fromthe group consisting of the sodium, potassium, lithium, rubidium and thetetraorgano ammonium cations, d is the valence of the cation representedby M and has a value of 1 and e has a value from 1 to 3 inclusive, saidparts by weight of said groups in the copolymer being based on 100 partsby weight of the copolymer.

2. The process of claim 1 wherein the metal is iron and the aqueousliquid is an aqueous ethylene glycol solution.

3. The process of claim 1 wherein the metal is aluminum and the aqueousliquid is an aqueous ethylene glycol solution.

4. An improved inhibited alcohol composition comprising an alcohol and acorrosion inhibiting amount of a copolymer as defined in claim 1.

5. The composition of claim 4 wherein the alcohol is ethylene glycolthat is admixed with water.

6. The process of claim 1 wherein the groups defined in part (1) of theclaim are present in an amount from 15 to 45 parts by weight per 100parts by weight of the copolymer and the groups defined in part (2) ofthe claim are present in an amount from 55 to 85 parts by weight per 100parts by weight of the copolymer.

7. The composition of claim 4 wherein the groups defined in part (1) ofthe claim are present in an amount from 15 to parts by weight per 100parts by weight of the copolymer and the groups defined in part (2) ofthe claim are present in an amount from to parts by Weight per parts byweight of the copolymer.

References Cited UNITED STATES PATENTS 2,762,785 9/1956 Cooper 260--29.23,111,534 11/1963 Sommer 252389 X 3,121,692 2/1964 Morehouse 252-753,198,820 8/1965 Pines et al. 252-75 X LEON D. ROSDOL, Primary Examiner.

JULIUS GREENWALD, Examiner.

M. WEINBLATT, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,341,469 September 12 1967 Arthur N. Pines et al.

at error appears in the above numbered pat- It is hereby certified ththat the said Letters Patent should read as ent requiring correction andcorrected below.

Column 10, line 50, for "CS2(OH)CH(OH)CH2" read CH2(OH)CH(OH)CH2 Signedand sealed this 18th day of March 1969.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

1. A PROCESS FOR INHIBITING THE CORROSION OF METALS BELOW SODIUM IN THEELECTROMOTIVE SERIES THAT COME IN CONTACT WITH AQUEOUS LIQUIDS SAIDPROCESS COMPRISING ADDING TO THE LIQUID A CORROSION INHIBITING AMOUNT OFA COPOLYMER CONSISTING ESSENTIALLY OF: (1)FROM 0.1 TO 99.9 PARTS BYWEIGHT OF (A) A MEMBER SELECTED FROM THE GROUP CONSISTING OF SILOXANEGROUPS REPRESENTED BY THE FORMULA: